Exemplary embodiments of the present invention relate to a method for representing the drift values of an aircraft with the drift values being represented in a vector representation.
During a non-autonomous, sensor-assisted helicopter landing in restricted viewing conditions, for example brownout or whiteout conditions, the pilot must be presented with an easily detectable, unique representation of the drift direction and drift speed of the helicopter above the ground. The implementation of such symbols in an HMI (Human-Machine Interface) is performed either on a head-down display (multifunctional display MFD), on a head-up display (HUD) or a helmet-mounted sight display (HMS/D). The common practice is to represent the drift velocity by a so-called drift vector (reference 1, FIG. 1), that is to say a line (with or without representation of the start point and endpoint) starting from a fixed endpoint (typically the center of the area represented), the length of the line being directly proportional to the instantaneous drift speed, and its direction specifying the instantaneous drift direction (see, for example, Szoboszlay, Z. et al., “Brown-Out Symbology Simulation (BOSS) on the NASA Ames Vertical Motion Simulator,” American Helicopter Society 64th Annual Forum, 2008).
The value range to be represented for the drift speed above ground in the landing phase is typically very large. A typical display range for landing helicopters is between 30 and 0 knots (kts). The problem that results therefrom for the above-described, proportional representation is that the HMI of the drift display must, on the one hand, represent the smallest lateral drifts during landing in a clearly detectable fashion, since these are classified as highly critical from the point of view of flight permission (the critical maximum value of the lateral drift is, for instance, 0.4 kts for a type CH53 helicopter), and, on the other hand, the display resolution of the display device is physically limited, and this restricts the representational length of the drift vector in terms of hardware. Thus, for typical HMI visualization concepts for the representation of the drift vector on conventional MFDs, the representation of a safety-critical drift value of 0.4 kts is done with a length of less than 5 pixels.
It is apparent that the pilot is no longer able to optically resolve the length and, in some cases, also the direction of the drift vector in the case of small drift values such as occur typically during landing in a reliable way on the display.
Exemplary embodiments of the present invention provide a method for representing the drift vector that produces a representation the pilot can easily detect even small drift values without the need to reduce the quality of the representation at higher drift values.
In accordance with exemplary embodiments of the present invention, for drift speeds below a prescribed threshold value a scaled representation of the drift vector length is provided that deviates from the known, purely proportional relationship between current drift velocity and the associated representation of length of the drift vector in the display device, specifically in such a way that the drift values below the threshold value are illustrated as extended in length (by comparison with the proportional representation). By contrast, the conventional proportional representation is adhered to in the speed range above the threshold value. A continuous transition is ensured between the two ways of representation, and so jumps in the representation are avoided.
It is advantageously possible to use a logarithmized representation.
The inventive method provides good visibility of the drift vector over the entire value range to be represented and, particularly in the case of small drift values. In particular, there is no need for a manual switching over between different resolutions of the display, or for the use of a plurality of display devices. It is therefore possible to make a substantial contribution to a risk-free, safe landing.